BY R. GREIG SMITH. 439 



In separating the bacteria both Abba's gelatine and dextrin- 

 meat agar were employed. The latter medium is prepared by 

 dissolving 20 grins, of agar in 1000 c.c. of ordinary meat extract 

 in the autoclave. After clarification with white of egg, 10 c.c. 

 of the mixture are pipetted into warm water and neutralised to 

 phenolphthalein with tenth-normal sodium hydrate. The calcu- 

 lated quantity of normal sodium hydrate is added to the bulk, 

 together with - 5 grm sodium carbonate; 20 grms. of dextrin 

 or gum acacia, dissolved in a small quantity of water is added, 

 and the medium boiled, filtered, placed in test tubes and sterilised. 

 The water was allowed to flow from the tap for half-an-hour upon 

 a sterilised watch-glass supported upon a tripod. From the watch- 

 glass the water was taken up into a sterile graduated pipette and 

 added to the previously melted and cooled gelatine (30° C.) or agar 

 (42° C); the tube was then shaken and the contents poured into 

 Petri dishes, which, after setting, were inverted and incubated 

 at the requisite temperature (15°, 18° or 22°). When the colonies 

 had grown sufficiently, inoculations were made upon sloped agar 

 and in gelatine (stab). When a diagnosis could not be made 

 from these — and this was the case when the organisms were 

 obtained for the first time — a series of gelatine plates were pre- 

 pared. The colonies that developed on these plates were used 

 both for the diagnosis of the organism and for obtaining a pure 

 culture. Generally the cultures obtained from the primary 

 (water) plates were impure. 



Having obtained a pure culture of an organism, inoculations 

 were made upon the ordinaiy media, which included peptone- 

 meat-agar, peptone-meat-gelatine, peptone-meat-bouillon, glucose- 

 peptone - meat - gelatine, lactose - peptone - meat - gelatine peptone- 

 meat-bouillon with 0*5% nitrate of potassium, ordinary potato, 

 and ordinary defatted milk. With the exception of the potato 

 and the milk, all the media were neutralised with sodium hydrate 

 to phenolphthalein as has been described. In observing the 

 motility, a portion of a young agar culture was transferred to a drop 

 of normal saline and examined. If the organisms apjjeared non- 



